Use lodash on the server as well as the client

It seemed more than a little strange that we were using lodash on the
client side but underscore on the server side. So I fixed that.

I've also been a bit more honest about the lib we are using as lodash
does differ from underscore in places
Default axis config, merge module specific config

It would be great not to have to add this config to all of the JSON
files, so instead I've set some defaults (using Ben's work in
no-realistic) which can be overriden.
Merge pull request #246 from alphagov/default-axis-labels

Default axis labels